Delegates from 189 countries have descended on Bonn, Germany, for two weeks of talks aimed at spurring on the United Nations-led effort to fight climate change. The lynchpin of these efforts remains the Kyoto protocol. But some feel that the totemic agreement is in danger of being marginalized by nations with different agendas, not least Canada, whose environment minister is chairing the talks.

What's on the agenda?

There will be two parallel sets of talks: one to discuss the Kyoto protocol by the 163 countries that have signed up to it, and the other to address the United Nations Framework Convention on Climate Change (UNFCCC). This agreement, which involves all 189 countries, calls for members to search for new technologies and projects to reduce greenhouse emissions without imposing strict reduction targets such as those imposed on many Kyoto nations.

The chief item for debate for Kyoto signatories is what should happen to the agreement after 2012, by which time industrialized nations have pledged to reduce their greenhouse emissions by an average of 5%, but developing economies have not had any fixed targets. This arrangement was intended as a show of leadership from richer countries, but has fostered resentment among those who see it as a free ride for prospective heavy polluters such as India and China.

So why are some people concerned about Canada chairing the sessions?

There have been complaints that Canada's recently elected conservative government seems anti-Kyoto, making it odd for environment minister Rona Ambrose to be at the helm of the talks.

Canada pledged to deliver a 6% cut in emissions over 1990 levels by 2012, but is currently emitting 35% more. Ambrose has threatened to break with Kyoto after that date if Canada's limits are not relaxed.

Would it matter if Canada bowed out?

A fair question, given that the country is responsible for only 2% of world greenhouse emissions (contrast that with Canada's neighbour to the south, which emits around a quarter of the world's greenhouse gases).

But Canada's position could be seen as symbolic of a growing feeling that Kyoto might have to be drastically remodelled if it is to survive.

If not Kyoto, then what?

Canada would then be likely to join Australia, India, Japan, China, South Korea and the United States in the Asia-Pacific Partnership on Clean Development and Climate. This agreement, which does not feature mandatory emissions targets, emphasizes investment in clean technologies. Canada argues that because of its paltry emissions and high-tech power base, it is in exactly the right place to be freed from the emissions limits and allowed to concentrate on developing cleaner energy.

Kyoto is still the bigger of these two agreements, representing some 62% of world emissions compared with around 50% for the Asia-Pacific group (some nations are involved in both). But Canada's recent lurch in the direction of technology and away from hard emissions limits could mark a shift in this balance.

Is that a bad thing?

The official line from the UNFCCC is that the Asia-Pacific group's efforts are valuable. "We see them as extremely important," acting head of the UNFCCC, Richard Kinley, told a press conference in New York last week. "If there is concern in the international community," he added, "it is that these technologies look quite far into the future. We would perhaps like to see a bit more in the short term."

Such as?

The Bonn meeting will also include discussions of other options open to UNFCCC members. These will include new initiatives for preventing deforestation, led for the first time by the forested countries themselves. There will be talks aimed at boosting efforts to capture greenhouse gases and bury them underground. And there will be discussions to bolster green projects such as clean-burning stoves and the capture and use of climate-warming gases from farm animals.

What does all this mean for the Kyoto agreement?

It's not clear. It could take on a radically altered form, perhaps even with emissions targets scrapped altogether. The longer commitment period may be extended, possibly to 2030, but this would frustrate those keen to see action as soon as possible. Others have called for industrialized nations to commit to far more stringent cuts of as much as 30%. Whatever happens, it seems unlikely that everyone will be satisfied by the outcome.